EP1336031B1 - Device for adjusting the rotation angle of the camshaft of an internal combustion engine in relation to a drive wheel - Google Patents

Description

The invention relates to a device for the relative rotation angle adjustment Camshaft of an internal combustion engine to a drive wheel according to the genus of Main claim.

From DE 196 23 818 A1 a generic device is known in which with With the help of a locking element arranged in the rotor of the camshaft adjuster the camshaft adjuster can be locked in one end position. About to Hydraulic lines carrying the locking element can be made from the locking element be transferred from its locking position to an unlocked position. Is the The camshaft adjuster can be unlocked by hydraulic adjustment of the rotor relative to the drive wheel of the camshaft, the timing of the intake or Exhaust valves can be changed in the desired manner. The in DE 196 23 818 A1 Device shown is designed so that the pressurization to the Hydraulic chambers, through which the adjustment of the rotor relative to the stator of the Camshaft adjuster and the hydraulic pressurization to Unlocking the locking pin is done in parallel. However, this is not always safe that the adjustment unit is unlocked before the rotor via the pressure or hydraulic chambers formed in the adjustment unit into a Adjustment position is transferred. This can result in operating states in which the Adjustment unit does not work reliably.

DE 198 25 287 A1 shows a camshaft adjuster in which the Pressure oil supply to the working chambers via that provided in the camshaft adjuster Locking element is controlled. With the transfer of the locking element in the unlocked position releases the locking element a pressure channel and the in Camshaft adjusters trained at the same time over to the Channels leading chambers pressurized with oil.

It is the object of the invention, a generic device to improve that starting noises when activating the Camshaft adjuster can be prevented or reduced and the life or Functionality of the locking unit is increased.

This object is achieved according to the invention by the features of the main claim.

In contrast to the locking unit shown in DE 198 25 287 A1 Camshaft adjuster is advantageously by a first adjustment stroke Locking element first transferred to an unlocking position, but in the both the hydraulic channel controlled by the locking element and that to the other oil supply holes leading to pressure chambers are still closed. Becomes however, the locking element is raised beyond its unlocked position, so the hydraulic channel leading to the pressure chamber of the adjustment unit is released before after a short initial adjustment travel of the rotor of the adjustment unit, also those to oil supply holes leading to the remaining pressure chambers are released and so that the rotor continues in the desired manner relative to the stator of the adjusting unit can be adjusted. This type of pressurization causes a rattling start of the camshaft adjuster prevented or reduced; the soffit can continue of the locking element can be reduced in the locking hole. So that will the lifespan and functionality of the locking device have been significantly improved.

Further advantages and advantageous developments of the invention result from the Subclaims and the description.

The locking element is received in a hole that is in a web or Wing of the rotor is arranged. The hole is in a hydraulic oil supply line arranged, which leads to a pressure chamber arranged in the adjusting unit. is the locking element is in a locked position, the hydraulic line closed by the locking element; in an unlocked position that gives Locking element free the hydraulic line to the pressure chamber.

An embodiment of the invention is in the following description and Drawing explained in more detail.

Fig. 1a einen Längsschnitt durch die Verstelleinheit,

Fig. 1b einen Schnitt entlang der Linie IB-IB in Fig. 1a,

Fig.1c einen Schnitt entlang der Linie IC-IC in Fig. 1a,

Fig.1d einen Schnitt entlang der Linie ID-ID in Fig. 1a,

Fig.2a bis Fig. 5c verschiedene Betriebszustände der Verstelleinheit in Verstellrichtung.

Show it

1a shows a longitudinal section through the adjustment unit,

1b shows a section along the line IB-IB in Fig. 1a,

1c shows a section along the line IC-IC in Fig. 1a,

1d shows a section along the line ID-ID in FIG. 1a,

2a to 5c show different operating states of the adjustment unit in the adjustment direction.

Description of the embodiment

In the drawing, the camshaft of an internal combustion engine is schematic with 2 indicated, at the free end of the rotor, hereinafter referred to as inner part 4, an adjusting unit 6 is arranged in a rotationally fixed manner. The inner part 4 is in the present Embodiment provided with three radially arranged webs 8a to 8c, the from a hub 10 of the inner part 4 go out. The inner part 4 is in the area of its webs 8a to 8c by a cellular wheel 12, which has three inwardly projecting radial Web 14 a to 14 c is provided. That representing the stator of the adjustment unit 6 Cell wheel 12 is on its end facing the camshaft 12 by a Sprocket 16 completed that rotatable and sealing on the hub 10 of the Inner part 4 is guided. The sprocket 16 serves to drive the camshaft for example via a control or drive chain connected to the crankshaft he follows. The opposite end face of the cellular wheel 12 is supported by a disk 18 closed, the sprocket 16, the disc 18 and the cellular wheel 12 not over Screw means shown are firmly connected. Through the webs 14a to 14c of the cellular wheel 12 are three by the chain wheel 16 and the disc 18 in axial Direction limited cells formed by the webs 8a to 8c of the inner part 4 in each two pressure spaces 22a to 22c and 24a to 24c are divided. The inner part 4 and the cell wheel 12, which is rotatably guided on this, are attached by means of a screw the camshaft 2 attached. For this purpose, the hub 10 has a central bore 28, which in the camshaft 2 is continued and one with a smaller one Connected diameter bore 30 in which the screw 26th is attached. The pressure spaces 24a to 24c are three in the hub 10 of the inner part 4th arranged and radially running bores 32a to 32c with an annular space 34 connected, which is between the fastening screw 26 for the adjusting unit 6 and the wall section provided in the hub 10 and in the camshaft 2 central bore 28 forms, the annular space 34 through the head 36 of the screw 26 is closed at the end.

The annular space 34 is provided with a plurality of bores 38 running radially in the camshaft 2 connected to an annular groove 40 arranged on the outer circumference of the camshaft 2. Three further bores arranged on the outer circumference of the hub 10 and running radially 42a to 42c are on the one hand depending on the rotational position of the inner part 4 opposite the cellular wheel 12 (explained in more detail later) with one of the three Pressure spaces 22a to 22c connected; on the other hand, they are with a Outer periphery of the camshaft 2 arranged annular groove 44 connected axially over five in the camshaft 2 bores 46a to 46e to another, also on Guide the outer circumference of the camshaft 2 formed annular groove 48.

The two ring grooves 40 and 44 are each via a acting as a rotary union Camshaft bearing 50 connected to two control lines 52 and 54 leading to one Control valve 56 designed as a 4/2 proportional control valve. The Control line 52 is connected to the output A of the control valve 56, while the Control line 54 leads to the output B of the control valve 56. That has on the input side Control valve 56 via a pressure port P, which has a check valve 58 and a Pressure medium pump 60 is connected to an oil tank 62 and via a connection T, which also leads to the oil tank 62.

To lock the inner part 4 with respect to the cellular wheel 12 in a manner according to FIG. 1 3 to 3 of the end position of the adjusting unit 6 is a bore 64 in the web 8a provided in which a locking element, hereinafter referred to as locking bolt 66 designated, is arranged The bore 64 is formed as a stepped bore, in which larger bore section 64a the head portion of the ring shoulder 66a Locking bolt 66 is guided, while in the smaller bore section 64b Stepped bore 64 of the actual locking bolt 66 is guided. The Locking bolt 66 has an opening 68 in which a compression spring 70 is arranged between the bottom of the opening 68 and one on the disk 18 supporting plastic disc 72 arranged in the bore section 64a is clamped. The plastic disc 72 has a central opening 74 which over a channel, not shown, is connected to the oil tank 62 Moving the locking bolt 66 against the spring force of the compression spring 70 in leakage oil from the opening 68 escape.

A stepped bore 76 is made in the sprocket 16, in a first Bore section 76a of the locking bolts 66 for locking the inner part 4th engages with the sprocket 16 or the cellular wheel 12. This follows in Sprocket 16 a second bore portion 76b, which is smaller in diameter is formed as the diameter of the locking bolt 66. On the outer circumference of the smaller bore section 64b, which is used to receive the locking bolt 66 is used, a crescent-shaped groove 78 is arranged, which extends into the stepped bore 76 extends into and communicates with the second bore portion 76b.

A radial through bore 80 is arranged in the web 8a, on the one hand, with the axial bore 46a and communicates with the annular groove 44 and on the other Leads to groove 78. In the web 8a there is also a connection channel Bore 82 provided, that of the larger bore portion 64a in the radial direction leads to the pressure chamber 22a

In the present exemplary embodiment, the adjusting unit 6 with its in FIGS. 1 to 3 provided end position for the adjustment of an intake camshaft, wherein the cellular wheel 12 is driven clockwise and the inner part 4 in Clockwise in the direction of "early" opening of the intake valves can be adjusted.

The adjustment process is described in more detail below with reference to the figures:

The internal combustion engine is in the position shown in FIG. 1 Operation, i.e. at standstill. The locking bolt 66 is in its locked Position, i.e. it is through the compression spring 70 in the bore portion 76a of the sprocket 16 locked So that the inner part 4 is opposite the cellular wheel 12 in one End position which corresponds to a "late" opening or closing time of the cam and Cam follower actuated intake valves of the internal combustion engine corresponds. The Control valve 56 is de-energized, so that via the output A of the control valve 56, the Control line 52, the annular groove 40, the radial bores 38, the annular space 34 and the radial bores 32a to 32c the pressure oil supply to the pressure chambers 24a to 24c is released for the starting process of the internal combustion engine.

Does the engine have a certain idling speed after starting reached, the control valve 56 is energized and thus the pressure oil supply to the Output B switched (see Fig. 2). The pressure oil supply now runs over the Control line 54, the annular groove 48, the axial bores 46a to 46e to the annular groove 44. From the annular groove 44 on the one hand the three radial bores 42a to 42c and on the other hand, the bore 80 leading to the locking bolt 66 with pressure oil fed. The pressure oil supply via the radial bores 42a to 42c to the three Pressure chambers 22a to 22c is still blocked because in the end position of the Camshaft phaser the radial bores 42a to 42c from the radial webs 14a to 14c of the cellular wheel 12 are covered or sealed (see FIG. 2c). The oil passage leading to the locking bolt 66 (bore 80), however, is open, so that he through the one below his ring shoulder 66a and the one on his face 66b oil pressure developing from the bore section arranged in the chain wheel 16 76a is lifted out and thus the adjusting unit 6 is unlocked. The Pressure oil supply to the end face 66b of the locking bolt 66 takes place via the groove 78 leading to bore section 76b.

In the unlocking stroke a of the locking bolt 66 shown in FIG. 2, however the bore 82 arranged in the web 8a and leading to the pressure chamber 22a still through shoulder 66a closed; only when the locking bolt 66 through the applied oil pressure is raised beyond the unlocking stroke a, is via the Control edge of the shoulder 66a released the opening of the bore 80. The bore 80 is fully released when, as shown in Fig. 3, the head part of the Locking bolt 66 comes to rest on the disk 72 (unlocking stroke b).

The hydraulic oil thus passes through the bore 80 into the pressure chamber 22a. The system is designed so that at an adjustment speed of the internal combustion engine Hydraulic oil supplied to the pressure chamber 22a, the inner part 4 by the angle α clockwise adjusted (see Fig. 4b). This initial adjustment path means that the inner part 4 arranged radial bores 42a to 42c from their complete overlap the radial webs 14a to 14c of the cellular wheel 12 out, so that Hydraulic oil via the radial bores 42a to 42c into the pressure chambers 22a to 22c arrives.

As can be seen in FIG. 5, the inner part 4 can thus face the adjusting unit 6 the cellular wheel 12 up to a maximum adjustment angle α 'in the direction of "early" opening of the inlet valves can be adjusted.

If the engine speed is reduced, the control valve 56 is no longer energized. In order to is switched back to output A and the pressure chambers 24a to 24c with Pressurized oil supplied. So that the inner part 4 is counterclockwise in again In the direction of its original locked end position Pressure chambers 22a to 22c located pressure oil is via the outlet B of the Control valve 56 returned to the oil tank 62. The inner part 4 reaches its original end position, the locking bolt 66, if it is in Overlap with the bore section 76a arranged in the chain wheel 16, in the latter fall in and thus lock the camshaft adjuster again. That in Hydraulic oil located in bore section 76a can then pass through the second one Bore section 76b and the groove 78 escape.

The control described above, in which the locking bolt of the Camshaft adjuster itself a valve function for the supply of hydraulic oil to the Exercises pressure rooms is not limited to the described embodiment. It can also be used with camshaft adjusters that generally have one Have locking mechanism and which a clear time sequence of Unlock and adjust should be assigned. These include, for example So-called axial camshaft adjuster, in which one in the housing part (stator) of the Camshaft adjuster arranged hydraulic piston is guided longitudinally and via a helical toothing with the part connected to the camshaft in a rotationally fixed manner (Rotor) of the camshaft adjuster works together. Due to the helical teeth the axial displacement of the piston in an angle of rotation adjustment of the camshaft implemented. Here, too, a locking unit locking the piston can operate simultaneously the previously described valve function for the supply of hydraulic oil to the pressure chamber of the Take over the camshaft adjuster. The control for unlocking and adjusting is can of course also be used for camshaft adjusters that are based on exhaust camshafts from Internal combustion engines are arranged.

Claims (2)

1. A device for adjusting the angle of rotation of a camshaft of an internal-combustion engine relative to a drive wheel, comprising an adjusting unit (6) which has an inner part (4) connected in a rotationally fixed manner to the camshaft (2), wherein the adjusting unit (6) has a cellular wheel (12) surrounding the inner part (4) and comprising a plurality of cells which are distributed over the circumference and bounded by crosspieces (14a to 14c) and which are each divided into two pressure chambers (22a to 22c and 24a to 24c) by crosspieces or blades (8a to 8c) of the inner part (4), the crosspieces or blades (8a to 8c) being angularly movable within the cells, and the camshaft is rotatable relative to the cellular wheel (12) between two end positions via the crosspieces or blades (8a to 8c) when the pressure chambers are pressurised or relieved of pressure, and wherein a movable locking member (66) co-operates with at least one complementary member in the respective other of the two components cellular wheel (12) or inner part (4), the locking member (66) is arranged in a hydraulic line (80, 82) leading to a pressure chamber (22a) and only opens the hydraulic line (80, 82) to the pressure chamber (22a) when it is in an unlocked position, and bores (42a to 42c) leading to the pressure chambers (22a to 22c) are provided in the inner part (4), the openings of the bores (42a to 42c) being closed by the crosspieces (14a to 14c) of the cellular wheel (12) when the adjusting unit (6) is in the fixed end position, characterised in that the locking member (66) is movable into a first unlocking position in which both the bore (82) in the crosspiece (8a), controlled by the locking member (66), and the bores (42a to 42c) in the inner part (4), leading to the pressure chambers (22a to 22c), are still closed, and in that the locking member (66) is movable into a second unlocking position in which first the bore (82) leading to the pressure chamber (22a) is opened by the locking member (66) and, after an initial displacement path (α) of the inner part (4), the bores (42a to 42c) leading to the pressure chambers (22a to 22c) are also opened.
2. A device according to claim 1, characterised in that the locking member (66) is accommodated in a bore (64) of a crosspiece (8a) and in that the bore (64) is connected to the pressure chamber (22a) by a bore (82) provided in the crosspiece (8a).

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